Nowadays various kinds of power devices are widely used, as this brings a series of convenience and benefits in technical and economical sense, it makes the power supply network increasingly affected by pollution, in which two of the most prominent problems are the harmonic pollution and reactive power pollution. On the other hand, modern electronic equipments have increasingly high power quality requirements on the power grid, while the increasingly serious pollution in the power grid in turn damages these sensitive electronic equipments, which results in the life of modern electronic devices becoming shorter and shorter.
Thus, the elimination of pollution from harmonic and reactive power becomes an important research topic in power electronics technology. In order to reduce or even eliminate pollution from harmonics and reactive power to a power grid, various countries have proposed the concept of “green grid”, and various kinds of power quality devices capable of eliminating the harmonics and performing reactive power compensation came into being. Now, a variety of power quality devices has undergone an unprecedented development, and has been widely used in industries with severe harmonic pollution such as buildings, railway, metallurgy, steel rolling, and machinery manufacturing industries. With the development of high-power switching technology, the traditional passive compensation devices (such as capacitance compensation cabinet, etc.) are gradually replaced by active power quality devices (such as active power filters, static var generator, etc.), and the active power quality devices have become dominant in the development.
For example, a typical structure of an active power quality device may be configured as following: a control apparatus samples the information of the power grid or loads of a power supply network, obtains instruction information containing components of harmonics and/or reactive power of the loads, so as to control power switching devices of the power quality device, and feed back the signal generated by the power switching devices to the power grid.
At present the control apparatus of an active power quality device is mainly configured as single-core based control apparatus. As shown in FIG. 1, the single-core based control apparatus controls the power switching devices of a power quality device by a single processing unit. It has the following features: all functions of detecting power quality and analyzing power quality measurements or instruction tracking control, are implemented by one processing unit, thus the degree of integration is high. However, it has the following disadvantages: 1) due to large amount of computing, it has higher requirements on the performance of the processing unit, for example, the computing speed of the processing unit is required to be faster; 2) the manufacturing cost of the power switching devices is also higher.